Electric starter motor systems for internal combustion engines

ABSTRACT

In an electric starter motor system the battery of the vehicle is connected across the armature of the field winding through a first switch, and connected across the armature is a second switch and a resistor in series. The first switch is normally open and the second switch normally closed, and the switches form part of a solenoid having a short-circuited winding. When the solenoid is energized, the normally open switch closes but there is a delay before the normally closed switch opens as a result of the short-circuited winding.

United States Patent Inventor John Godfrey Wilson West Sutton Coldfield, England Appl. No. 835,977

Filed June 24, 1969 Patented June 8, 197.]

Antigua: Joseph Lucas (lnduutrlen) Limited lllrmlngham. England Priority July l5, I968 Great Brltaln 33622/68 ELECTRIC STARTER MOTOR SYSTEMS FOR INTERNAL COMBUSTION ENGINES 2 Claims, 2 Drawing Figs.

us. Cl 290/38, 318/250, 318/430 Int. Cl "02p 1/18 Field of Search 318/250,

[56] References Cited UNITED STATES PATENTS 897,538 9/1908 .lanisch & Naumann..... 318/250 l,605,977 1 [H926 Oswald 318/250 2,774,925 I 2/1956 Wagner 318/250 3.221.234 ll/l965 Ault Primary Examiner-Orin L. Rader Assistant Examiner-K. L. Crosson Attorney-Holman and Stern ABSTRACT: In an electric starter motor system the battery of the vehicle is connected across the armature of the field winding through a first switch, and connected across the armature is a second switch and a resistor in series. The first switch is normally open and the second switch normally closed, and the switches form part of a solenoid having a short-circuited winding. When the solenoid is energized, the normally open switch closes but there is a delay before the normally closed switch opens as a result of the short-circuited winding.

PATENTED JUN 8 \am KT 5ENEYS ELECTRIC STARTER MOTOR SYSTEMS FOR INTERNAL COMBUSTION ENGINES This invention relates to electric starter motor systems for use in internal combustion engines.

An electric starter motor system according to the invention comprises in combination first and second terminals which in use are connected to a battery, a normally open switch connected in series with the armature of the motor and the field winding of the motor between said first and second terminals, a normally closed switch connected in series with a resistor across the armature, the normally open switch and the .normally closed switch being part of a solenoid which includes a short-circuited winding, said short-circuited winding serving ,when the solenoid is energized to provide a delay between closing of the normally open switch and opening of the normally closed switch, the arrangement being such that during the delay period the motor is operated at reduced power but with full field current.

The switches are conveniently operated by plungers coaxially mounted within the solenoid with one plunger slidable within the other, with the short-circuited winding carried by one of the plungers.

In the accompanying drawings, 7

FIG. 1 is a circuit diagram illustrating one example of the invention, the solenoid used in the circuit being shown in diagrammatic form, and

FIG. 2 is a sectional side view showing a second example of a solenoid. 1

Referring to the drawing, there is provided a battery 11 having its negative terminal earthed, and its positive terminal connected through a pair of normally open contacts 12 to one side of the armature 13 of a starter motor, the other side of the armature 13 being earthed through the field winding 14 of the starter motor. Moreover, the armature 13 is bridged by a pair of normally closed contacts 15 in series with a resistor 16, which may be an actual resistor, or may be constituted by the resistance of the lead between the contacts 15 and the junction of the armature 13 and winding 14.

The contacts 12, 15 form part of a solenoid 17 having an E- shaped core 18 on the central limb of which is mounted a winding 19, one side of which is ea'rthed, and the other side of which is connected to the positive battery terminal through a starter switch 21. When the winding 19 is energized, it attracts a pair of plungers 22, 23 to close the contacts 12 and open the contacts 15 respectively, but opening of the contacts 15 when the winding 19 is energized is delayed for a predetermined period of time by a short circuit winding 24 woundon one of the outer limbs of the core 18.

When it is desired to start the engine of the vehicle with which the parts are associated, the starter switch 21 is closed to energize the winding 19 and close the contacts 12. Current now flows from the battery through the field winding 14 and the armature 13, it being appreciated that full field current flows in the winding 14, but, by virtue of the resistor 16, only a reduced current flows in the armature 13. Thus, the motor operates at reduced power. After the predetermined period of time, the switch 15 opens so that the resistor 16 is no longer in circuit, and the motor then operates at full power. The delay enables a starter pinion associated with the starter motor to engage with a toothed wheel on the engine before full power is applied, and in a modification, the switch 15 is not associated with the solenoid, but opens automatically when the pinion and tooth wheel engage.

When the starter motor has started the engine, the switch 21 is allowed to open so that the winding 19 is deenergized. As a result, the contacts 12 open to break the circuits to the starter motor, and the contacts 15 close to short circuit the armature, thereby contributing dynamic braking.

In FIG. 2, parts functionally equivalent to those in FIG. 1 are indicated by the same reference numerals. The solenoid shown includes a body 31 supporting the windin 19 and its associated plunger 22, which 18 axially slidable in t e body and includes an extension 22a for operating the contacts 12 as shown. The plunger 23 is axially slidable within the plunger 22 and incorporates an extension 23a slidable within the extension 22a and serving to operate the contacts 15. Both plungers are spring-loaded to their normal position, and the winding 24 is in the form of a sleeve carried by the plunger 23.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. An electric starter motor system for an internal combustion engine, comprising a combination a battery, a starter motor having an armature and a field winding, an E-shaped magnetic core having a central limb and first and second outer limbs, a first winding on said central limb, means connecting said firstwinding'in series with a first switch across said battery, an earthed winding on the first outer limb, a first plunger normally spaced from said central limb and said second outer limb, but attractable into engagement with said central limb and said second outer limb, a second plunger normally spaced from said central limb and said first outer limb, but attractable into engagement with said central limb and said first outer limb, a contact carried by said first plunger and forming part of a second switch, said second switch being open when said first plunger is spaced from said central limb and said second outer limb, but being closed when said first plunger engages said central limb and said second outer limb, means connecting said second switch in series with said armature and said field winding across said battery, a contact carried by said second plunger and forming part of a third switch, said third switch being closed when said second plunger is spaced from said central limb and said first outer limb, but being open when said second plunger engages'said central limb and said first outer limb, said system further including a resistor, and means connecting said third switch in series with said resistor across said armature, closing of said first switch resulting in closing of said second switch, followed by opening of said third switch after a delay caused by said short-circuited winding.

2. An electric starter motor system for an internal combustion engine comprising in combination a battery, a starter motor having an annature and a field winding, a body part, a first winding supported by said body part, means connecting said first winding in series with a switch across said battery, a first plunger slidably mounted in said body part with said first winding surrounding said first plunger, a contact carried by said first plunger and forming part of a second switch, resilient means urging said first plunger to a position in which said second switch is open, means connecting said second switch in series with said armature and said field winding across the battery, a second plunger slidably mounted within said first plunger, a short-circuited winding carried by said second plunger, a contact carried by said second plunger and forming part of a third switch, resilient means urging said second plunger to a position in which said first switch is closed, a resistor, and means connecting said third switch in series with said resistor, and means connecting said third switch in series with said resistor across said armature, closing of said first switch resulting in energization of said first winding, moving said first plunger to close said second switch, and said second plunger moving to open said third switch after a delay caused by said short-circuited winding. 

1. An electric starter motor system for an internal combustion engine, comprising a combination a battery, a starter motor having an armature and a field winding, an E-shaped magnetic core having a central limb and first and second outer limbs, a first winding on said central limb, means connecting said first winding in series with a first switch across said battery, an earthed winding on the first outer limb, a first plunger normally spaced from said central limb and said second outer limb, but attractable into engagement with said central limb and said second outer limb, a second plunger normally spaced from said central limb and said first outer limb, but attractable into engagement with said central limb and said first outer limb, a contact carried by said first plunger and forming part of a second switch, said second switch being open when said first plunger is spaced from said central limb and said second outer limb, but being closed when said first plunger engages said central limb and said second outer limb, means connecting said second switch in series with said armature and said field winding across said battery, a contact carried by said second plunger and forming part of a third switch, said third switch being closed when said second plunger is spaced from said central limb and said first outer limb, but being open when said second plunger engages said central limb and said first outer limb, said system further including a resistor, and means connecting said third switch in series with said resistor across said armature, closing of said first switch resulting in closing of said second switch, followed by opening of said third switch after a delay caused by said short-circuited winding.
 2. An electric starter motor system for an internal combustion engine comprising in combination a battery, a starter motor having an armature and a field winding, a body part, a first winding supported by said body part, means connecting said first winding in series with a switch across said battery, a first plunger slidably mounted in said body part with said first winding surrounding said first plunger, a contact carried by said first plunger and forming part of a second switch, resilient means urging said first plunger to a position in which said second switch is open, means connecting said second switch in series with said armature and said field winding across the batterY, a second plunger slidably mounted within said first plunger, a short-circuited winding carried by said second plunger, a contact carried by said second plunger and forming part of a third switch, resilient means urging said second plunger to a position in which said first switch is closed, a resistor, and means connecting said third switch in series with said resistor, and means connecting said third switch in series with said resistor across said armature, closing of said first switch resulting in energization of said first winding, moving said first plunger to close said second switch, and said second plunger moving to open said third switch after a delay caused by said short-circuited winding. 